Lubricating grease composition



. BEERBQWER "ET A| LUBRICATING GREASE COMPOSITION HOPPER.

i.; H 2 mi a WZOJMS@ www??? w ,w OW C sept. 21, 1943.l

Filed Deo. 29, y1945 ys1 1.21, 1948. A. BEERBQWER am 2,449,580

LUBRICA'IING GREASE COMPOSITION CHILL En Patented Sept. 21, 1948 AlanBeerbower, Westfield, and John C. Zimmer,

Union, N. J., assignors to Standard Oil DevelopmentCompany, acorporation: of Delaware Application December 29, 1945, SerialNo.638,431

e claims. (014252-375 1, `This ,invention relates Ato aluminum soapgreases, `and in` particular to aluminum soap vgreases containingphenolic compounds.

`In `the lubricating industry, aluminum soap greases have a particularlyimportant place` as being outstandingly suitable for the lubrication ofmoving parts which require a measure of adhesiveness to the metalsurfaces and good cohesion Adhesiveness in a of the grease composition.grease is important for the lubrication of parts such `asthe chassis ofautomobiles and crawler typetractors in which conditions prevailinvolving sudden shock causing splattering of the lubricant and exposureto a water-laden environment.

`Greases suitable for thelubrication of such parts .are distinguishablefrom the strongly `adhesive and coherent greases which are elastic incharacter and which show a greater tendency to separate from the metalparts and to ball up rather than to string out as required in such typelubrication. Aluminum soap greases are outstanding in their lubricationof chassis parts and for crawler type tractors. The present invention isconcerned with an aluminum soap grease particularly suitable in thelubrication of `such parts and in the use of a sm-all amount ofresorcinol "as a crystallization modifier permitting the preparation. ofaluminum soap `grease under` more advantageous conditions vthan theprior art procedure of pan cooling.

The extensive use of aluminum soap greases has been somewhat curtailedby reason of difficulties of manufacture.l The main difliculty in thepreparation of aluminum soap greases is in regard `to the obtaining ofthe desiredhomogeneous stringy structure. The desirable structure forthe grease compositions has beenobtainable in the past only by thevlaborious and slow pan cooling method. It has generally been consideredthat this slow cooling was necessary in order to avoidthecrystallization of the aluminum stearate as the main soap constituent inthe mineral oil after the high temperatures necessary for blending. Forsome time past, crystallization modifiers `have been found which permitthe rapid cooling of aluminum soap greases. The present inventionrelates to the use of resorcinol as a particularly advantageouscrystallization modier in the rapid temperatures `aslow as` 859 F. andin layersof about 1A," `thick to temperatures as low as 50; F.

without granulation or decomposition.` This use `of resorcinol .permitsthe preparation` of `aluminum soap greases on .a large-scale,`continuous basis and facilitatesthe packaging of the grease directlyfrom the cooling devices into` large shipping containers withoutreworkingor filtering.

`This advantageous effectof resorcinol hasbeen found to occur, moreover,without the development of1 any disadvantageous effect upon .thelubricating quality of the mineralen-aluminum soapblend. In` additionalso, resorcinolfin the grease compositions is-.not adversely aiected bythe incorporation of accessory additive materials such :as oilthickening `agents or anti-corrosive or anti-oxidation agents.

Thus, vthe present invention relates tothe manufacture of highlystabilized `aluminum soap grease compositions containing resorcinolasvthe special additive `agent for a grease mixture `of suitable mineral.oil base and aluminum soap"o`f a saturated fatty acid containingbetween 10 and 22 carbon atoms in the molecule, such as aluminumstearate. vThe amount in'which the kresor- `cinol is advantageouslypresent to exertthe crystallization inhibiting and stabilizingeffectwupon the final composition i varies usually `between 0.075% and3% by weight ofzthe total final composition. The preferable range ofconcentration of the resorcinol is between 0.1% and 1%. In suchcompositions, the aluminum soap is blended with the mineral `oil toforma grease of suitable composition in amountsbetween 3% and ,20%, but`usuallybetween 3% and 10%, by weight of thev oil. Accessory ingredientsto impart tothe composites other desirable characteristics include freeunsaturated fatty acids containing fromyl() to`22 carbon atomsinthemolecule andtheir aluminum soaps, naphthenic acids andtheir aluminum`soaps and` "oil-thickening agents `such as latex or polybutene.

, The outstanding effect of the resorcinol appears lto beconnectedprimarily with the compounding and cooling` steps in the preparation ofthe greases. It appears that the resorcinol functions in ,the `aluminum.soap-mineral oil cooling of aluminum soap greases from the high amountsbetween 0.075 and 3% is incorporated the mineral oil-aluminum soapblends at temperatures of about 275-350 F., the composites can be cooledrapidly in bulk with agitation to blends `to permit rapid coolingYwithout crystallization of the aluminum soaps. Thus, the resorcinolpermits` the mixture after compounding` `to belagitated duringcoolingand the transitionin structureto occur at lower temperaturesythan hithertofore in vessels of even/100 lbs. capacity. The resorcinolalso exerts a denite but minor l 3 stabilizing effect upon the cooledblended composition.

In preparing the grease compositions of this invention, the oil employedis preferably derived from a naphthene base crude, as for example oilsof the Coastal type. The viscosity of the oil is usually above about 85seconds Saybolt at 210 F., and preferably from 50 110.200 secondslSaybolt at 210F. The'aluminum soap and the resorcinol are added totheoil at a. temperature between about 130 F. and 150 F. The heating maybecarried out in a coil type heater or in the usual type kettle. Asuitable heating 'kettleisfurnished with mechanical means of agitation,

usually 'paddles having at the outersweepsclose fitting scraperadjustments to pass over its inner surface in order to insure good heattransfer and to obviate the development of surface r`iilms. Usually thealuminum soap an-d the resorcinolare blended with about to 20% of thetotal quantity of the oil to be used and the mixture worked Linto. athick non-lumpy paste. This paste-is then stirred into the balance yofthe oil, and heated to `atemperature of between 280 F. and 300 F. andyheld at this temperature until all of the soap and fresorcinol arethoroughly incorporated to form 'ya smooth homogeneous `mass. The massafter -heating is then rapidly cooled by passing through coolingequipment to a temperature of about 90 FF. "lThe cooling may be affectedby passing the material into shallow pans and then returning the'cooligrease to mixing equipment wherein the mixture vis allowed'tosettle to about the transition "temperature On the other hand, thematerial "may be rapidly cooled byY passing through Aany type `offjacketed `equipment and preferably throug-hafscraped Surface typecooler.

Another means of preparing-the grease is to firstg form: a slurrywith asmall quantity of the *oil base material and the aluminum soap and they'resorcinoL and then to pass the slurry through an vori-nce mixer towhich is also supplied the further :quantitiesA of oil as:are-requiredto lprepare the ,'nishedI-grease. eThe mixture-is thenpassed .through a coil heater at a temperature of about ,300YF. and thenallowed to settle tov permit the .separation ofany occluded'gases beforepassing .through-a scraped surface cooler. By this means xagrease canbesatisfactorily prepared in large l,quantities ona continuous basis, andthe product .directlypassed to the shipping containers from .the coolingequipment.

n --An illustration of the method of preparing the ,grease involving theuse of the usualtype: kettle r`for heating and blending the constituentsis af- Jforded by the following description which should be read inconjunction with the drawing presented asv Figure 1.

,"Figurev 1 shows a jacketed kettle I0 fitted internally with paddles lI having scraper terminals I2 which can be nely adjusted to work uponthelentire surface `of the kettle. The motion of the Apaddles in theAkettle insures verycomplete and thorough agitation `within the kettle.The jacket portion I 3 of the kettle l0 is adapted for the passing *inthrough line I4 and the passing out through line I5 of steam eitherunder normal or superatmospheric pressure as temperatures within thevkettle l0 require. Under the conditions of such means of agitation andof a temperature between about' 280F,'and about 330 F., suiiicient 1-oilof suitable character as a mineral oil base for the ipreparation of thegrease composition is supplied from storage tank IB to the kettle l0through linef l'lrandadmixed'with the aluminumsoap and A4 resorcinolsupplied through opening I8 to make a smooth thick paste. Furtherquantities of oil to make the grease of desired consistency are thensupplied through line l1 and the mass agitated until a smoothhomogeneous composition is obtained.

When the mass in the kettle has become smooth and homogeneous, themixtureispassed from the *bottom ofthe kettle through line I'9 to ascraped surface chiller 2U. The chiller 20 has an outer jacket 2lthrough which a cooling medium, usually water, pa-sses in through line22 and out 1 through'lineZS. v'The scraper rotor 24 is operated by themotor 25 through gear box 26 and transmission 2'l. lThe .cooled greasepasses from the chiller through linev 28.

Inbatch operation the cooled grease is recycled through line 428 tothekettle l0. By such recycling the entire quantity of grease compositionisbrought to about the transition temperature at about the same time.When this temperature -within the mass is reached, agitation Within-'the`kettle is'discontinued and the mass yis allowed to settle and to coolfurther until the` transition in structure has been satisfactorilyeffected. -The gel composition is then removed from the kettle4throughfa T 29 on line I9and passed to shipping containers.

"In continuous operation itis usual to employ a series of kettlessimilarly equipped to that'fdesignated by the numeral I0 and'v to passthe hotmixture to the chiller in aA relatively continuous stream fromthe various kettles through tl'ieTv 30 Ion line 19. In this manner ofoperation'lthecooling eifected in the chiller 20 is more complete thanthat in batch-operation, namely, the cooling in the chiller is effectedto about the'tran'sition temperature. The cooled grease insuch operationis passed directly'through a T 3| on line`28 Ato the shipping containerswherein setting and further cooling to atmospheric temperature areeffected.

Figure 2 indicates a second processing method by which the grease can beprepared. `According to this process the oil is passed fromr asupply-tank 40 through `lines 4l and 42 into a countercurrent rapidbatch mixer 43. To the mixer 43 isalso added through the hopper 44 therequired vamounts of aluminum soap and resorcinol; l"Ifhe oil, thealuminum soaps andthe resorcinol are added in quantities so as to form afree owing slurry composition. The slurry is then passed f' 'To th'esurge tank may also be suppliedthrough line an oil thickening agent,ysuch as polyvbutene or latex, from thetank 5l. .Thegrease mixture isremoved from the surge tank ..54 through the line 5S and passed to thescraped surface chiller 59, which is cooled by thevwater jacket 60. Thegrease .is cooled usually therein to a ltemperature of about l00:F. andthen passed directly through pipe 6| to the shippin containers 62.` I v.

Ifhefollowing examples arepresented to :illustrate the prepa-ration;andrvarious characteristics `ofV suitable" greases prepared according tothis invention:

Escample 1 A grease of theiollowing composition was preparedz Thealuminum stearate and one-sixth' of the lubricating oi] were charged t-oa heating kettle as illustrated in Figure 1, and the mixture agitated bymeans of the paddles for about l5 minutes. Then the remainder oflubricating oil, preheated to about 100 F. was added and agitationcontinued. The resorcinol and polybutene solution were then added andthe temperature of the mixture raised to about 300 F. At this point theheating was discontinuedand the mixture cooled by passing cold waterthrough the kettle jacket. The grease was thus cooled with agitation toabout 95 F., then agitation discontinued and the mass allowed to standfor 21/2 hours. The grease after this period of standing was found to beof a smooth plastic gel nature, The grease so prepared had an unworkedpenetration at 77 F. of

275 and a worked penetration at 77 F. of 350.

Example 2 A grease of th'e following composition was prepared:

Per cent Resorcinol 0.27 Aluminum stearato 6.50 Lubricating oil of 70 S.U. vis/210 F 93.23

The materials were charged to a kettle as in Example 1, and heated to310 F. The hot fluid grease was then pumped to a scraped surfacechiller, 3.1125 inches .in inside diameter and 36 inches in insidelength. The scraper consisted of two sets of blades, placed on oppositesides of the rotor, and hinged so as to be forced against the tube wallby their motion. The rotor was operated at 365 R. P. M. The grease wasfed to the cooler at the rate of 2.48 pounds per minute, giving anoutlet temperature of l96 F. (The water entered at 60 F. and left at 72F.) The grease was drawn into containers and allowed t0 stand overnight,at which time it was found to be a clear, homogeneous plastic gel. Itsunworked penetration at 77 F. was 279, and its Worked penetration at 77F. was 375.

Thus, it has been shown that satisfactory aluminum soap greases can beprepared in the presence of `resorcinol from blends of th'e soaps of thesaturated fatty acids containing between and carbon atoms in themolecule, such as aluminum stearate, in viscous oils by rapidly coolingfrom the compounding temperatures to almost normal temperatures. Thisrapid cooling to atmospheric temperatures permits the grease products tobe packaged directly into bulk shipping containers. The discovery ofthis effect of resorcinol obviates the timeand labor-consuming and thecostly prior art process of preparing the aluminum soap greases bypan-cooling and subsequent reworking, and also avoids the `consistencyloss based upon the quantity of aluminum soap employed. It would seemthat the action of the resorcinol has basis in preventing therecrystallization of the aluminum soaps at tem- 6 peratures below about`140'\F.",'th`at is, a'n `eifeot inV grease compositionssimilar to` thatof pour depressants in waxy mineral oils inhibiting the crystallizationof the wax content. Thuatheuse of resorcinol permits departure fromtheprioi art procedure of` being able to cool `the greasetto minimumtemperatures of about 140 F. and then having to continue the preparationof the grease by pan-cooling, by 'allowing the hot grease mixture `to becooled with agitation to temperatures well below 140 F. In this mannergreases having a worked penetration at 77 F. of between about and about360 or higher 'may be easily and readily prepared.

'Ihe advantages of the use of resorcinol in the preparation of aluminumsoap greases .are attained without loss of any of the desirableproperties of aluminum soap-mineral oil grease composites. It would seemthat in the grease products containing resorcinol, the advantageousrelationship between the various constituents in suring good lubricatingquality is attained and that in addition there is exerted an addedstabilizing effect. In other words, it appears that a ininor portion ofthe composition exists as a co1- loidal dispersion of the soap compoundsin a relatively stable emulsion of a major portion or a colloidaldispersion of other soap compounds in the mineral oil of suitableconsistency. This relationship, as indicated by tests, such aspenetration, adhesiveness to metal surfaces, internal cohesion, meltingpoint, etc., is considered important in order that there is formed onthe bearing surfaces a satisfactory adhesive lubricating :lilm while thecolloidal phase functions to offer substantial resistance toward heatconduction from the surface iilm into the mass thereby minimizing theeiect of friction, speed and load during service upon the bulk of thegrease composition.

The present invention is not to be limited by any theory of manufactureor to any particular type of aluminum soaps, but only to the followingclaims or their equivalent.

What is claimed is:

1. Process lfor preparing a lubricating grease which comprisesthoroughly mixing at a temper-- ature sufficiently high to cause thesoap to dissolve in the oil, a viscous hydrocarbon oil, grease formingproportions of an aluminum soap of a saturated fatty acid containingbetween about 10 and 22 carbon atoms in the molecule, and 0.075 to 3% ofresorcinol based on the total com position, rapidly cooling the heated`mixture in a owing stream by artificial chilling substantially belowthe normal transition temperature of about F., and then allowing themass to stand. i

2. Process for preparing aluminum soap greases which comprisesthoroughly mixing at a temperature sufficiently high to cause the soap`to dissolve `in the oil, a viscous mineral lubricating oil, about 3 to10% of aluminum stearate and from about 0.1% to 1.0% of resorcinol basedon the total composition, rapidly cooling the heated mixture byartificial chilling of a flowing stream of said mixture to a temperaturesubstantially below normal transition range of about 140 F. and allowingthe mass to stand.

3. Process for preparing semi-fluid aluminum soap greases for thelubrication of chassis parts of crawler-type tractors which comprisesthoroughly mixing at a temperature suiciently high to cause the soap todissolve in the oil, a viscous mineral lubricating oil of between15G-200 secrsqzvcinol.based nth'eiiqpal -composition, rapidly Thefollowing references are of Iecordir-1` ghe cbplipg heh'eaedgmixpurle.by artificial Chilling me 0f '0h15 Patent: -iiilfflgwiqgspram jto a.gmperatpref about 5 UNITED STATES PATENTS. 90% M9695", F Y@md lthen,-allwing the. mixture t0 Number Name 'D666l 2,031,966 Stratford et a1.Feb. 25, '1936 2,062,346 21111111611 e1; @1, Dec, 1, ,1636ALANBEERBOWER. 2,065,657 Hilnker Dec, 2,91966 JOHN c.` znviMER. 102,394,567 sprouie en a1.v Feb.' 12,5 A194@

